1. Field of the Invention
The present invention relates to a lithium titanium oxide material and a method of manufacturing the same.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98
A lithium-ion battery is one type of rechargeable battery in which lithium ions move from a negative electrode to a positive electrode during discharge, and move back to the negative electrode when the battery is charged.
The lithium-ion battery has aqueous electrolyte, which includes a solvent and a lithium salt dissolved in the solvent. The lithium salt includes lithium hexafluorophosphate (LiPF6), lithium perchlorate (LiClO4), and lithium tetrafluoroborate (LiBF4). The solvent may include ethylene carbonate, dimethyl carbonate, and diethyl carbonate.
Traditionally, the anode of the lithium-ion battery is made of carbon. When the lithium-ion battery is charged, especially at a charging voltage between 0.4 and 0.9 volts, a solid electrolyte interface (SEI) is easily formed on the carbon anode. The formation of SEI, which is irreversible, causes the battery to have high irreversible capacitance, approximately in a range of from 30 to 55 mAh/g, to easily self-discharge, and to generate excess heat, causing a safety issue.
The anode manufactured using lithium titanium oxide has good structural stability and long cycle life, will not easily react with electrolyte, and is not subject to the occurrence of lithium deposition. The three-dimensional structure of lithium titanium oxide spinel allows lithium ions to intercalate and de-intercalate easily. Due to the above advantages, lithium titanium oxide is suitable for manufacturing anodes for high charge and discharge current applications.
However, according to research, lithium titanium oxide has poor electrical conductivity (around 10-13 S/cm), and the charge and discharge rates are limited by the particle sizes of the material. Thus, an improvement is needed for increasing the electrical conductivity.